Apparatus for electromagnetic suspension and guidance of tracked cars

ABSTRACT

In the apparatus disclosed current is supplied to electromagnets which suspend and / or guide the cars that travel along tracks in an electromagnetic suspension system. The current is alternately supplied along two mains from a single generator. One main exhibits the voltage rated for the electromagnets of the car and the other a voltage which is higher than the rated voltage by an order of magnitude. The higher voltage main supplies high voltage pulses or shock currents for stabilizing cars which deviate slightly from the normal path along the track in response to transverse winds or other transverse forces.

United States Patent 1191 Karch 1 51 Apr. 3, 1973 [s41 APPARATUS FOR3,569,792 3/1971 Schaffersmann ..317/123 ELECTROMAGNETIC SUSPENSION3,638,093 1/1972 Ross ..104/ 148 MS AND GUDANCE 0F TRACKED CARS FOREIGNPATENTS OR APPLICATIONS [75 Invent: Lud'ig Germany 643,316 4/1937Germany ..104/14s MS [73] Assignee: Messerschmitt-Bolkow-BlohmGesellschatt mit besclhrnnkter Hai- Primary Examiner-Gerald M. Forlenzatung, Munich, Germany Assistant Examiner-George H. Libman [22] Filed, ol 1971 Attorney-Torch and McGeady [2!] Appl. No.: 185,521 [57] ABSTRACTIn the apparatus disclosed current is supplied to elec- [30] ForeignApplication Priority Data tromagnets which suspend and or guide the carsthat travel along tracks in an electromagnetic suspension Oct. 27, 1970Germany ..P 20 52 599.9 system The current is alternately pp along twomains from a single generator. One main exhibits the '8 "104/148 6voltage rated for the electromagnets of the car and the I other avoltage which is higher than the rated voltage [58] Field Sal-104,148148 by an order of magnitude. The higher voltage main supplies highvoltage pulses or shock currents for stabilizing cars which deviateslightly from the normal (56] References Cited 'path along the track inresponse to transverse winds or ED T E A N other transverse forces.

3,307,884 3/1967 Dunlap et'al. ..308/l0 8 Claims, 6 Drawing Figures L LF' O 5 Manama 5' sominsromirr i f c i j i Fig.2

5TRANSFORMER Fig.4

MAGNET MAGNET REGULATORS ELECTRO- PATENTEBAPR 3 ms THRESHOLD AilELECTRO- BACKGROUND OF THE INVENTION This invention relates to cars suchas railway cars which are magnetically supported and or guided relativeto a track, and particularly to electrical equipment for holding themagnetically suspended vehicles along thetrack.

In such cars or vehicles electromagnets of high supporting capacitysuspend and guide the cars relative to a track or track arrangement.Exact maintenance of the distance between the cars and the trackarrangement is necessary, and rendered possible by controlling theexcitation of these electromagnets. Rapid load changes,

" particularly those resulting from sudden strong air blasts on carsmoving at high speed, can be compensated for by exciting theelectromagnets momentarily with sudden pulses or in a manner similar toa shock excitation. This requires applying short term voltages of veryhigh values. These adverse forces that disturb the normal forward travelof the cars may appear at any time and with varying intensities. Sincethese times and intensities cannot be determined in advance, thecompensating current supply for the electromagnets must be such thataparticularly high voltage is always available.

Because of the above, known magnetic suspension systems for high-speedtrains employ such a high volt-' age as the operating voltage for theelectromagnets. Depending upon the layout of the electromagnets, thevoltage can be to times higher thanthe rated or operating voltage of theelectromagnets. If a generator is to supply the sum'of the ratedcurrents of all the electromagnets at this high voltage, it must becapable of delivering a correspondingly high rated power. Such agenerator is thus very heavy. This means that the cars carry heavy,poorly utilized generators. This disadvantage also applies when theelectric power is fed from a stationary power system, because at leastone emergency generator must be available in the car when this currentsupply fails.

An object of this invention is to improve such apparatus.

Another object of the invention is to avoid such heavy generators forelectromagnets in the cars of a track-bound train suspended and orguided by them. The track-bound train should be understood as any landvehicle whose track or path is fixed.

SUMMARY OF THE INVENTION mains are fed from a central main or networkwhose rated voltage is higher than that of the electromagnets by aboutan order of magnitude. One of the two mains fed from the central mainreceives its energy over a transformer. The term main is used herein inthe singul ar to mean an electrical supply network, including all theconductors carrying the current.

According to another feature of the invention, the rated voltage of thecentral main is lower than the rated 2 voltage of the operating main onthe secondary side of the transformer.

In any case, however, a voltage is provided which is one order ofmagnitude higher than the rated voltage of one of the operating mainsand serves as a supplemental voltage, not the operating voltage, for theelectromagnets. The rated voltage of the other operating main is lower.

According to another feature of the invention, the high voltage main iscontrolled so that the electromagnets are fed briefly and only when airblasts or other sudden outside thrusts act on the vehicles. As long asno force changes or only minor force changes are required, the power isfed from the low voltage main whose rated voltage corresponds to theoperating voltage of the electromagnets.

With such a current supply, a primary generator feeding the central mainneed substantially be powered only for the sum of the rated powers ofall electromagnets arranged on the car or train. When the electric poweris fed from the high voltage main the primary generator is overloaded.However, the overload is of extremely short duration and thus withoutsignificance. The additional electric power delivered by the generatoris only higher by a small percentage than the sum of the rated powers ofall electromagnets. As a rule, all electromagnets of the cars do notrequire supplemental energy at the same time to compensate for airblasts. Rather they are energized in succession because the air blastsmove along a train of cars with the speed at which the cars moveforward.

In view of this fact, and according to another feature of the invention,the additional electric power is obtained from electromagnets which haveto be energized briefly, if necessary, .without having to be energizedmore first.

These and other features of the invention are pointed out in the claims.Other objects and advantages of the invention will become obvious fromthe following detailed description when read in light of theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. 1 shows a block diagram of a current supply for electromagnetswhich serve as supporting or guide magnets in cars of a suspensionrailway;

FIG. 2 shows a gap feeler;

FIG. 3 shows an acceleration transmitter;

FIG. 4 shows a current gate arrangement;

FIG. 5 is a diagram for a current supply of another embodiment'of theinvention and 7 FIG. 6 shows a car section as well as a configurationfor the magnetic suspension and guidance of the same.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS Referring to the drawings,in particular, the invention embodied therein in FIGS. 1 to 5,electromagnets 1 are mounted on a car C. The electromagnets suspend andguide the car C along a track T. Each electromagnet 1 includes itsexciter or energizing coil.

Feeding of electric power to the electromagnets l is effectedselectively from two operating mains 2 and 3 of different voltage. Asingle three-phase generator 5 energizes the main 2 directly and theother main 3 over a threeephase transformer 4 from a central main 6.Electromagnets 1 are connected to the mains 2 and 3 over current gatearrangements 7 and 8. These current gate. arrangements may, for example,be composed each of three thyristors 20, 21, which, as is known, areeach actuated by a so-called threshold regulator 22, respectively 23;the latter determine the trigger point of the thyristors 20,respectively 21 depending on the respective input voltage of theregulators 22, 23. Regulator 9, connected with both threshold regulators22 and 23, ensures that at one time only one current gate arrangement isconductive while the other is blocked.

This regulator 9 is a known analog computer which ac- 1 tuates at acertain threshold value of its output voltage either the thresholdregulator 22or the threshold regulator 23 in the customary way,employing a voltagesensitive commutator (not shown), for instance a Z-ener diode. It should be noted that additional electromagnets areconnected in the same manner to the mains 2' and 3. v

The generator has a rated voltage which is higher I than the ratedvoltage of the electromagnets 1 by at least one order of magnitude. Itsrated power correspondsa'pproximately tothe sum of the rated powers ofall electromagnets arranged on one or several cars. Transformer 4 isarranged so that it reduces the rated voltage of generator 5 to anoperating voltage which corresponds approximately to the three tofour-fold rated voltage of the electromagnets 1. This higher operatingvoltage is necessary so that, when all electromagnets are fed from themain 3 connected to the delivery side of thetransformer 4, the positionof the cars'with respect to the track arrangement, for example, becauseof inaccurate track position, can be corthen supplies the regulator 9with a corresponding measuring quantity 11. Naturally, each of theelectromagnets 1 is assigned an accelerationtransmitter which can besecured to the assigned electromagnet.

As a result of turning off the current gate arrange ments Sand tuming onthe current-gate arrangements 7, the electric power fed from the lowvoltage main 3 to the electromagnets 1 is cut off while the power fedfrom the main 2 to the electromagnets 1 is turned on. This power derivesdirectly from the high voltage generator 5 through the central main 6.The new voltage is applied briefly in the form of a sudden pulse similarto a shock excitation. The suddenly applied high voltage from thegenerator 5 has the effect of forcing a heavier exciter current to flowthrough the electromagnets 1 with only a minor delay. Damage to thegenerator 5 does not occur because the heavier current is required onlyfor an extremely short time. It is also not required at the same timefor all electromagnets of a car or train. The air blast moves along thecars so as to affect the acceleration transmitters successively alongthe car or cars. Thus, the electromagnets are connected successively tothe main 2 to pulses. I 7 It should be understood that according to anembodireceive their high voltage ment; of the invention the .car C isone of a number of cars forming a train. As the train passes aparticular point the air blast at that point strikes the carssuccessively. Thus, the reactions by the electromagnets need merely besuccessive.

rected by varying the exciter current. To this end a .ineasu'ringquantity designated by the; arrow. 10, originating, for example, fromknown gap feelers, is fed in known manner to t'he respective regulator9. For instance, each gapfeeler is a small electromagnet 24 (F IG. 2arranged on the base of the car C, whose coil 25 is connected withtheregulator 9 (F IG. 1) at 10. The

- electromagnet 24,- whose inductivity depends on the "distance, forinstance, to a magnetically conductive rail (not shown) of track T,supplies the measuring quantity 10, depending on the respective distanceto this rail, which determines the trigger point of the thyristors 20.

The start of the current gate's20. and the feeding of electric powerfrom the, associated main 3 is effected as .long as no outsideinterfering forces act on'the car.

When a sudden air blast strikes the car or part of the carlaterally, itproduces a lateral shock. An' acceleration transmitterlocated in the caror the part of the car thus shocked, produces a measuring quantityalong-the arrow. 11; This quantity constrains the regulator 9 to I turnoff the current gate arrangement 8 and turn on the 7 current gatearrangement 7. As illustrated, for instance,

in FIG. 3 the acceleration transmitter comprises a clamp 26 with a metalweight 29 held between its jaws 27 bya spring 28 a small electromagnet31 is attached,

to the cross-bar 30 of the clamp 26, whose coil 32 is connected with theregulator 9 (FIG. 1) at 11. If the .distance between the weight 29 andthe electromagnet 3 l alter,s due to a sudden blast striking the car orthe respective part of the car laterally, the electromagnet Someadditional electromagnets can be used for relieving generator 5. Thisapplies both to electromagnets which have already been energized to 'ahigher lev'el and which must be de-energized to some extent, and toelectromagnets which must be completely de-energized in a directionopposite to that of .the'main 2. For this purpose, for example only thecurrent gate -arran'ge-' 45- ment shown in FIG. 4 whereby athyris'to'r34 is assigned ments 7 (FIG; 1) may'each be replaced by thearrange:

to each thyristor 21, the former allowing passage of current in theopposite direction. Regulator 23 also actuates these thyristors 34.

According to these embodiments'of the invention,

there is a clear requirement for the, dimensioning of the generator 5. Acar such as C can, ,therefore, be

equipped with lighter and better utilized generators than was heretoforepossible. This is also important on cars or trains whoseelectromagnetsare energized from stationary mains. Such cars, asmentionedabove,

'- require an additional emergency current supply. Apart from that, thefrequency of the mains isusually so low that the current supply ispreferably effected only over frequency'transformers order to avoiddelays in the control of the excitation of the electromagnets. Ac-

cording to the invention weight is thus saved in these frequencytransformers. In this case, for instance, generator 5 need only becoupled mechanically with an electromotor 35 (FIG. 5). The electromotor35, for ex.- ample an single-phase AC. motor, is fed in a known mannervia a sliding contact-36 by a fixed main 37,

whose frequency is lower than that of the central main 6 of the car C.

According to another embodiment of the invention, generators with lowerrated voltages are used. The transformer 4 should then be arrangedbetween the central main 6 and the main 2 (not shown). In this case thetransformer constitutes a step-up transformer. Additional disconnectibleloads, such as lighting or heating systems can be connected, wherenecessary, to the mains 2 and 3.

lt should also be noted that the above-described electromagnets 1 canact on magnetically conductive rails of track T. As illustrated in FIG.6, for instance, electromagnets 1 can be arranged vertically as guidancemagnets along a car or train 38 to maintain the car or train between tworails 40 connected .via rail supports 39 with track T in midposition.Further electromagnets 1" functioning solely as supporting magnets arearranged horizontally on each side of flhe car; these suspend the car ortrain with respect to rails 40, respec-- tively track T. Each of theseelectromagnets (supporting as well as guidance magnets) is assigned onegap feeler 41 as well as one acceleration transmitter 42 each, wherebythe latter is attached to the assigned electromagnet 1' or 1",respectively. The electromagnets as well as the gap feelers andacceleration transmitters are thus located outside the car; as againstthis, the above-described generator 5, transformer 4 and the currentgate arrangements 7 and 8 together with the regulators 9, 22 and 23 aswell as the mains 2, 3, 6 (not shown) are arranged in the car, andshould most expediently be located in a separate area 43.

While embodiments of the invention have been described in detail, itwill be obvious to those skilled in the art that the invention may beembodied otherwise without departing from its spirit and scope.

6 What is claimed is:

1 An apparatus for a magnetic suspension car, comprising electromagnetmeans for supporting and/or guiding the car, first main means forcarrying electrical current of one voltage, second main means forcarrying current at a voltage higher than that of the first main means,and control means for coupling the electromagnet means to said firstmain means to suspend the car and responsive to external thrusts formomentarily coupling said second main means to the electromagnet meansto counter-act the effects of the thrusts on the car.

2. An apparatus as in claim 1, further comprising a central main forenergizing said first main means and said second main means.

3. An apparatus as in claim 2, further comprising transformer meansconnecting said central main to said first main means.

4. An apparatus as in claim 1, wherein the voltage carried by saidsecond mainmeans is higher than the rated voltage of said electromagnetmeans by one order of magnitude.

5. An apparatus as in claim 2, wherein the voltage of said central mainis lower than the voltage carried by at least one of said main means.

I 6. An apparatusas in claim 1, further comprising generator meanslocated in the car forenergizing said first main means and said secondmain means.

7. An apparatus as in claim 2, further comprising generator means forenergizing said central main.

. An apparatus as In claim 1, wherein said electromagnet means includesa plurality of electromagnets which are energized by said mainmeans,'and further comprising means for transferring electric power froman electromagnet that has been energized to an electromagnet thatrequires energization.

1. An apparatus for a magnetic suspension car, comprising electromagnetmeans for supporting and/or guiding the car, first main means forcarrying electrical current of one voltage, second main means forcarrying current at a voltage higher than that of the first main means,and control means for coupling the electromagnet means to said firstmain means to suspend the car and responsive to external thrusts formomentarily coupling said second main means to the electromagnet meansto counter-act the effects of the thrusts on the car.
 2. An apparatus asin claim 1, further comprising a central main for energizing said firstmain means and said second main means.
 3. An apparatus as in claim 2,further comprising transformer means connecting said central main tosaid first main means.
 4. An apparatus as in claim 1, wherein thevoltage carried by said second main means is higher than the ratedvoltage of said electromagnet means by one order of magnitude.
 5. Anapparatus as in claim 2, wherein the voltage of said central main islower than the voltage carried by at least one of said main means.
 6. Anapparatus as in claim 1, further comprising generator means located inthe car for energizing said first main means and said second main means.7. An apparatus as in claim 2, further comprising generator means forenergizing said central main.
 8. An apparatus as in claim 1, whereinsaid electromagnet means includes a plurality of electromagnets whichare energized by said main means, and further comprising means fortransferring electric power from an electromagnet that has beenenergized to an electromagnet that requires energization.